'vivisector' originates from Latin, specifically from the elements 'vivus' and 'secare', where 'vivus' meant 'alive' and 'secare' meant 'to cut'.

'vivisector' developed in English as 'vivisect' (verb) + the agent suffix '-or'. 'Vivisect' itself derives from Late Latin 'vivisectio' (from 'vivus' + 'sectio', from 'secare') and entered English via French/Latin influence as 'vivisection' and related forms.

Initially it literally meant 'one who cuts the living'; over time it came to mean 'one who performs experiments on living animals' and is often used in a strongly negative or pejorative sense.